Metal sheet stock, such as cold rolled or stainless steel or other iron stock or alloys, aluminum and aluminum alloy foil and sheet, copper and copper alloy foil and sheet and the like, is rolled to a thin gauge using oil as a pressure transfer medium ("rolling oil"). Metals subject to oxidation upon exposure to oxygen and moisture in the atmosphere are often protected from oxidation during storage by additional oils, greases and other hydrocarbon coatings ("shipping oils"). However, these coatings must be removed prior to application of more permanent coatings such as paint, chromium and the like.
Sheet steel that has been coated with organic materials including hydrocarbons can be cleaned by immersing in a solvent cleaner, such as perchloroethylene, but such solvents are increasingly difficult and expensive to dispose of safely.
Removal of materials such as oxides and hydrocarbons from metal surfaces can also be done by plasma cleaning, but this is generally expensive and large sheet cannot be accommodated in conventional plasma etch equipment at practicable rates.
Thus a practical method of cleaning sheet metal stock to remove organics and other coatings rapidly and inexpensively with a plasma continues to be sought.